I enjoy adding crown molding and wall frames to my home. The molding itself has brought tremendous intrinsic value and warmth to my home. Every chance I get I add more molding to my home. This study protractor is made of hard aluminum with solid and accurate markings that help me identify accurate angle readings, especially when working with imperfect corners and un-straight walls.Use the outer readings for Single cuts and the inner readings for Mitred cuts. It's pretty simple.